This invention relates to a fixture for supporting a vehicle transmission during a test procedure.
Transmissions are developed in test cells where the design and durability of the transmission can be evaluated. A typical test cell includes an electric motor for driving the transmission. A test cell may also include dynamometers that are coupled to one or more output shafts of the transmission. The test cell includes a test stand fixed to a bed plate that is permanently attached to the floor of the test cell. In preparation for a test, the transmission is brought into the test cell and fastened to the test stand. A unique headstock is used to support each type of transmission. Test stands are designed to avoid resonant frequencies (vibrations) in the operational speed range. To avoid resonances the fixtures are inherently stiff and heavy. Usually the test stand is not adjustable so that the rotational and tilting position of the transmission as it would be installed in a vehicle cannot be duplicated. As a result, the lubrication conditions of the transmission, for example, may not be accurately simulated by the transmission test.
Dynamometer test cells are very expensive so that it is important to maximize test cell time available to test transmissions. The installation and removal of transmissions in a test cell reduces the time that the test cell is available for a transmission test. To this end, there has been trend to provide carts that support the transmissions. The cart and transmission are rolled into the test cell and docked at a desired location within the test cell for testing.
Traditional test stands have been used with the carts. That is, a bed plate having a non-adjustable, fixed stand, secured to the bed plate. The solid, non-adjustable test stands have been used to prevent vibration of the transmission during testing.
What is needed is, adjustable test stand that is also portable. The requirement for portability and multi-axis adjustability requires a light but stiff headstock. A light structure which provides clear access to the transmission is to a certain amount flexible and consequently it is desirable to isolate unavoidable resonances by the use of damping elements.